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Transverse sections are necessary in the thigh because of
the superimposition of superficial veins. This problem no
longer applies in the leg, as the subcutaneous tissues are
thinner. On the other hand, the various networks form complex
anastomoses and hemodynamic circuits in a single plane. The
surface anatomy of these veins can therefore be easily studied
with the patient standing.
Perforating veins of the knee and leg are presumed to be involved
in the pathogenesis of varicose veins to such a point that
some authors have recommended systematic eradication of these
veins in order to prevent recurrence.
These perforating veins were initially classified according
to their level: lower third of the leg for low Cockett's perforators,
middle third for medial gastrocnemius perforating veins and
high Cockett's perforators, and finally, the upper third of
the leg for Boyd's perforators.
The first authors to systematically describe these vessels
attributed fairly constant anatomical sites, aligned along
an imaginary vertical line, called Linton's line. This line
is parallel to the long saphenous vein in the leg and lies
one fingerbreadth behind the medial malleolus.
From below upwards, the various perforating veins correspond
to Cockett I (precisely 67 cm from the ground), Cockett II
(13.5 cm), Cockett III (18.5 cm), and then the so-called "24-cm"
perforators. These veins communicate between the posterior
branch of the long saphenous vein in the leg (Leonardo's vein)
and the posterior tibial veins.
This constant site "perforator rule" is contested
by other anatomists. Some believe that the majority of perforating
veins of this region are located on collateral vessels connecting
the long saphenous vein to its posterior branch, while others
consider that they are situated randomly with a particularly
variable distance from the ground.
From an anatomical and functional point of view, these perforating
veins can be classified not according to their level of anastomosis,
but according to their position in relation to the saphenous
vein. The type of circuit in which they participate can be
more clearly explained on venous mapping.
We therefore propose to distinguish four types of perforating
veins in the knee and leg:
perforating veins anastomosing with the long saphenous vein
in the leg or on a localized diversion (Figure
62);

perforating veins anastomosing with an anterior or posterior
accessory saphenous vein in the leg (
Figure
63);

perforating veins anastomosing with tributaries of the saphenous vein in the leg or on the calf plexus (
Figure 64);

perforating veins anastomosing with intersaphenous communications
in the leg (
Figure
65).
The types of venovenous shunts observed can be defined by simultaneously
taking into account the anatomical situation of these perforating
veins and the hemodynamic circuit in which they participate.
Most of these perforating veins are globally attracted towards
the long saphenous. vein. They can nevertheless form complex,
independent hemodynamic circuits. Some of them are incompetent
during muscular systole and diastole, while others are only
incompetent during diastole (
Click
here ). Other circuits allow reentry of an overlying reflux.
They are also sometimes connected to each other by longitudinal
interperforator anastomoses responsible for recurrences.
The perforating veins of this region communicate with various
deep veins.
Perforating veins of the medial region below
the knee (Boyd's perforators) open into posterior tibial
veins or the tibioperoneal trunk. Variable numbers (3 to 6)
of usually indirect perforators are grouped together and arise
from an accessory saphenous vein or tributary. These small-caliber
vessels describe a long intramuscular course and are only rarely
responsible for massive reflux and are usually responsible for
varicosities of the medial regions of the knees.
Very rarely, a
great anastomotic vein can arise in the
region of Boyd's perforators. It remains a tributary to the
cutaneous branch of the anastomotic artery with which it perforates
the aponeurosis of the adductor canal. Draining into the femoral
vein, but only emerging from the aponeurosis medially below
the knee, this vein actually represents a variant of an adductor
canal perforating vein. It connects the femoral vein with the
saphenous vein in the leg or with the accessory saphenous vein
or tributaries.
Muscular perforating veins of the medial surface of the calf
anastomose with medial gastrocnemius veins. C. Gillot subdivides
them according to their site of muscular penetration into upper,
middle, and lower pole veins. Only the latter anastomose with
the short saphenous vein. These
medial gastrocnemius perforating
veins, generally indirect, with multiple branches and receiving
intramuscular branches, arise from a diversion of the long saphenous
trunk (
Figure
62), an accessory saphenous vein (
Figure
63), the calf plexus (
Figure
64), or an intersaphenous communication (
Figure
65). These medial gastrocnemius perforators are common and
are involved in recurrences and extension «of superficial
thromboses towards deep veins.
All of the so-called
Cockett's perforators anastomose
with posterior tibial veins. They may arise from Leonardo da
Vinci's vein, but also from communications between this vein
and the saphenous vein, a posterior accessory saphenous vein,
or tributaries. The more proximal veins often act as reentries
for an overlying reflux. The most serious vessels from a pathogenic
point of view are low Cockett perforators, situated one handsbreadth
above the medial malleolus with a short and direct course. Ectatic
Cockett perforators are difficult to access, but are palpable
well below the site of aponeurotic perforation, in a zone of
cellulitis which they generate or accentuate.
Perforating veins of the anterolateral region of the leg anastomose with peroneal
or anterior tibial veins. They are generally reentry perforating
veins for reflux derived from the anterior saphenous network
of the thigh. They can generate varicosities, but are only exceptionally
responsible for trophic disorders. All these perforating veins,
together with tributaries and accessory saphenous veins, constitute
a veritable long saphenous system. Any blood reflux will be
part of an original circuit, a venovenous shunt involving dilated
perforating veins which are either incompetent or reentry pathways
towards the deep veins.

Further reading
Dodd H., Cockett EB. The pathology and surgery of the veins of the lower
limb. Londres, Churchill Livingstone, 1976.
Fischer R., Fulleman N.H., Alder W. A propos d'un dogme phlébologique
sur les localisations des perforantes de Cockett. Phlébologie 1992;
45: 207-12.
Gillot C. Anatomie chirurgicale des perforantes de la jambe. Phlébologie
1987; 40: 563-74.
Staubesand J., Stemmer R. Études anatomiques sur la constance des
perforantes de Cockett. Phlébologie 1987; 40: 599-604.